Many semi-trailers have a front landing gear for support of the front of the trailer when the tractor is detached. Such landing gears generally have two spaced-apart, telescoping or Jack-type landing gear legs and feet which extend downwardly from the floor of the trailer. Each leg is operatively attached to screw and follower or a rack and pinion gear arrangement which is driven by a landing gear drive shaft which extends between the legs and which causes extension or retraction of the legs and feet depending on the direction in which it is rotated.
Traditionally, a hand operable handle or crank is attached to the landing gear drive shaft by a pin or bolt which serves as a hinge connection allowing the handle to be pivoted out of the way while not in use. Manual rotation of the handle in one direction causes extension of the feet and lifting of the trailer to, for example, separate the trailer from a semi-tractor, and requires considerable time and effort on the part of the person manually rotating the hand crank. Manually operated jack structures, however, are often difficult to use, require much time for their operation and expose the operator to potential injuries as he is positioned next to the trailer while turning the crank to raise or lower the landing gear to in turn raise or lower the trailer.
A number of devices for mechanically or electrically extending and retracting the landing gear of a semi-trailer are known. These devices are, in general, cumbersome and expensive and generally require installation of such devices on the semi-trailer at the time of installation of the landing gear thereon. Owing primarily to the complexity and expense of the prior art systems, they have not enjoyed widespread acceptance in the trucking industry. Also, the complexity of such systems has rendered them relatively fragile and therefore generally unsuited to the rugged environment to which over-the-road semi-trailers are subjected daily.
What is needed is a simple, adjustable motor mount system for easy installation beneath the floor of a semi-trailer which will allow rapid and easy alignment and attachment of the drive shaft of the motor to the crank shaft of the landing gear of the semi-trailer.